Oral

Background and aim:
Serum leucine-rich alpha-2 glycoprotein (LRG) and calprotectin have been studied as markers of disease activity in adults with inflammatory bowel disease (IBD). However, there have been no reports of comparing serum LRG with serum calprotectin in pediatric patients with IBD. The aim of this study was to clarify whether serum LRG or calprotectin is a better serologic marker to monitor disease activity in pediatric patients with IBD.

Methods:
Subjects under 17 years old undergoing care at 11 Japanese pediatric centers were retrospectively assigned to 3 groups representing Crohn’s disease (CD), ulcerative colitis (UC), and normal controls (NC) with irritable bowel syndrome or no illnesses. Serum LRG and calprotectin were measured using commercial enzyme-linked immunosorbent assay kits.

Results:
We enrolled 173 subjects including 74 with CD, 77 with UC, and 22 NC. Serum LRG concentrations in active CD (median, 200.3 μg/mL) were significantly greater than in remission (80.9; P<0.001) or NC (69.4; P<0.001). Serum calprotectin concentrations in active CD (2.94 μg/mL) also were significantly greater than in remission (0.96; P<0.05) or in NC (0.87; P<0.05). Serum LRG concentrations in active UC (134.3) were greater than in remission (64.8; P<0.01), but not greater than in NC (69.4), while serum calprotectin concentration in active UC (1.1) was not significantly different from remission (0.67) or NC (0.87). In ROC analyses of LRG, calprotectin, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) for ability to distinguish active IBD from remission, CD and UC showed areas under ROC curves for LRG (0.77 and 0.7, respectively) that exceeded those for calprotectin (0.69 and 0.64), CRP (0.71 and 0.68), or ESR (0.73 and 0.66).

Conclusions:
In pediatric patients with IBD, serum LRG may better reflect disease activity than serum calprotectin, particularly in CD.